This invention relates to a method of detecting defects in an object, for example, a bottle in which the degrees of scratches, cracks or breakage of objects to be examined such as beer bottles or juice bottles and the presence or absence of foreign matters in the objects are optically detected, and to a device for implementing the method.
In general, bottles used for beer, wine, carbonated drinks, food, etc. are recovered and used again. The bottles thus recovered are cleaned with a bottle cleaning device to remove foreign matters such as dust and leavings. However, the bottle cleaning device is unable to remove some of foreign matters stuck firmly to the inner wall of a bottle. Therefore, it is necessary to remove bottles having foreign matters from the bottling line before or after the bottle cleaning process. It is also necessary to remove bottles having cracks or scratches.
Various methods or devices for detecting bottle defect have been conceived or proposed, but they are associated with a disadvantage or another, which will be described in detail later.